Ecological Significance of Instream Hydrological Statistical Parameters

Hydrological parameters are significant both in hydrological events and ecological conservation. The implications of hydrological statistical parameters in river ecology were investigated by considering three basic parameters, as follows: (1)mean value, (2)coefficient of variation, and (3)extreme ratio. Four typical rivers selected as case studies include the Yellow and Yiluo Rivers in north China, and the Yangtze and Oujiang Rivers in south China. Hydrological statistical parameters were calculated using monthly flow data collected from the key hydrometric stations on each of the four rivers. The results revealed that the three hydrological statistical parameters are all crucial ecological indicators that reflect the ecological conditions of river ecosystems. The mean value of the flow may be the key determinant of habitat range and aquatic biomass. The coefficient of variation may reflect the stability or vulnerability of the ecological conditions of rivers, and the extreme ratio may reflect the variation degree of the stability or vulnerability of river ecology. The results may provide some references for research in the river ecological water requirements and conservation of river ecosystems. (C) 2013 American Society of Civil Engineers.